Insomnia is a major mental health symptom related to depression, sleep loss, sleepiness, mistakes, accidents, irritability and anger. Major contributors to insomnia include periodic limb movements (PLM) in sleep and restless legs (RL). Night-to-night variability and expensive, inconvenient testing limits clinical and research work with these conditions. This project will develop technology needed to produce a self- contained, easily-used, ambulatory leg activity monitor (LAM) that will detect and record over several days the occurrence of characteristic periodic movements. The data, transferred to a Computer are analyzed for PLM and RL rates. This provides the first objective measurement of all naturally occurring RL and of all PLM over several nights. The LAM technology uses piezoelectric sensors to detect activity and microprocessors to pre-process data by identification of candidate periodic movements and storage of periodicity information. This permits recording all periodic movements for 16 or more consecutive day. Phase 1 tests feasibility of accurately capturing and correctly identifying all periodic movements. Phase 2 will serve to establish the LAM as a very user-friendly standard for diagnosis, severity assessment, screening and treatment evaluation. The LAM may provide efficient early detection of neuroleptic induced akathisia for psychiatric patients.